综合色区无码一区,亚洲综合一区国产精品,日韩亚洲性爱无码视频,国产白丝护士AV在线网站,国产三级视频播放线观看,亚洲五月综合缴情在线观看,aⅴ变态另类天堂无码专区

您現(xiàn)在的位置: > Language Tips > Easy English > Odd Question  
 





 
Who invented the pencil?
[ 2006-07-14 10:48 ]

鉛筆是大家從小用到大的東西。不知道你用鉛筆的時(shí)候有沒(méi)有想過(guò)它到底是怎么來(lái)的。想了解一下鉛筆是誰(shuí)發(fā)明的和怎么制作的嗎?趕快看看下面這篇文章吧!

Pencil, a derivative of the Latin word pencillus for "little tail," originally described a small, fine, pointed brush.

N. J. Conte, in 1795, successfully produced pencils, after the later famed Faber family of Nuremberg, Germany, failed to do so, by using a pulverized graphite base to create a substandard, crude prototype of a pencil. Conte's method, the basic recipe used by all pencil manufacturers today, differed from the failed Faber fiasco, as he ground graphite, mixed it with certain types of clay, pressed the "dough" into sticks, and finished them in a kiln. The Faber family followed suit, and achieved the fame and fortune that previously eluded it.

The recipe used by modern pencil manufacturers, calls for dried, ground graphite, a form of carbon, mixed with clay and water in varying proportions. Pencils made with more clay produce a harder pencil, and, conversely, pencils made with more graphite produce a softer pencil. In either case, the ingredients are mixed until they reach a doughy consistency, and then pass through a forming press, which presses the dough into a pencil thin, smooth, glossy rope. After workers straighten the rope they cut it into the desired lengths, and bake them in industrial ovens.

While the mixture is prepared and baked, workers prepare the casing that will house the lead. They shape the wooden casings, made from either red cedar or pine, into halves, and carve grooves in them to encase the graphite-based leads. The workers then carefully insert the finished leads into the grooves, glue the two wooden halves together, run the resulting slats through a saw that cuts them into single pencils, and finish them with a shaping machine that smoothes the pencils' surfaces.

Modern pencils come in over 350 varieties; each designed for a specific use, and may be purchased in over 72 colors. Black pencils, or graphite-based pencils, come in 19 degrees of hardness and of intensity. Specialty pencil leads are crafted to write on surfaces such as cloth, cellophane, plastics, and movie film. Architects, engineers, and those doing outdoor construction work primarily purchase these specialty leads, as they possess non-fade, weatherproof qualities. The versatility of Conte's brainchild, the pencil, makes it the essential, indispensable tool of these trades.

pulverize: 研磨成粉

graphite: 石墨

kiln: 窯,干燥爐

doughy: 面團(tuán)似的

(英語(yǔ)點(diǎn)津 Annabel 編輯)

 
 

 

 

 
 

48小時(shí)內(nèi)最熱門

     

本頻道最新推薦

     
  Why are moths attracted to light?
  Pamplola Bull-running Fiesta(西班牙奔牛節(jié))
  Deaf-blind awareness week
  Hide-and-seek
  July 11






      <td id="nxi2y"></td>
      <th id="nxi2y"></th>
    1. <big id="nxi2y"><meter id="nxi2y"><thead id="nxi2y"></thead></meter></big>
        <rt id="nxi2y"></rt>
        <ins id="nxi2y"><meter id="nxi2y"><table id="nxi2y"></table></meter></ins>
      1. <noscript id="nxi2y"><tr id="nxi2y"><samp id="nxi2y"></samp></tr></noscript>
        <acronym id="nxi2y"></acronym>
        综合色区无码一区,亚洲综合一区国产精品,日韩亚洲性爱无码视频,国产白丝护士AV在线网站,国产三级视频播放线观看,亚洲五月综合缴情在线观看,aⅴ变态另类天堂无码专区 国产在线拍揄自揄视频网站 国产视频精品免费 少妇系列之白嫩人妻 白眼女网爆韩国网红御姐性爱视频 热闹的背后总有不 日本黄漫画免费播放 亚洲AV日韩Aⅴ中文无码 无码一级视频在线